You should definitely not rely on Adwords to give you an indication as to how viable of a business this will be. You'll need to test a handful of different marketing channels and determine ways to look for early indicators of success. This includes defining specific goals and making sure you understand the metrics that you'll need to hit at each point in your funnel to achieve the revenue goals you're after.

It sounds like you're also early-stage enough that you should also be doing some price sensitivity testing, iterating on your MVP based on early customer feedback, and doing plenty of user testing to ensure strong product adoption and a smooth onboarding and usage experience.

Happy to give you some more pointers if you'd like to discuss in greater depth. Best of luck!

I've spent years initially testing new businesses using Google Adwords and have a good understanding of what we should be looking for, and what happens next.

I think its awesome that you're only spending $4 a day with your test, and actually learning, so tell me more about what we are tracking.

So we have acquired 200 leads, and of those 7 have paid up. What do we know about the others? What information have they given us. Do we know if they come back to the site to look around? Are we engaging them in any other ways?

For $4 a day we can do lots and lots of things to figure out if this channel works, or indeed if our MVP is the right one to go with.

What I love about Adwords more than any other channel is the speed at which we can learn about our users. Are we talking to those 7 paying users yet?

Your question has inspired me to ask many more questions, but I'm hopeful answering all of this, and more, should allow you to squeeze out every last drop of value from this test, before doing anything else. And there is lots of other things we can start testing too, but first up, lets go really deep in to our Adwords test.

I can help you understand your data if you need, and get down all of the other items I mentioned in to a logical actionable work plan so you can make progress really quickly. Give me a shout if you need to. Best of luck.